This invention relates to .beta.-lactam antibiotics. In particular, it relates to intermediates of 1-carba(1-dethia)-3-cephem-4-carboxylic acids, and to a process for preparing certain intermediates to such compounds.
Hashimoto et al. in U.S. Pat. No. 4,335,211 disclose a class of 1-carbacephalosporins having potent oral activity. These compounds are currently being evaluated for the treatment of various conditions such as the common upper- and lower-respiratory tract infections caused by the pathogen H. influenzae. One such compound, known as loracarbef or LY163892, has shown activity against a broad spectrum of bacteria in laboratory tests. Loracarbef has proven to be a relatively stable compound which exhibits high blood levels and a relatively long half-life. Loracarbef is currently being clinically evaluated.
The 1-carbacephalosporins thus far have not been obtained from natural sources, for example, as microbial metabolites. Accordingly, methods for the total synthesis of these promising compounds are highly desirable, particularly methods which are adaptable to large scale manufacture.